Prenatal Programming of Neuropsychiatric Disorders: An Epigenetic Perspective Across the Lifespan

Humanity's evolved nest and its relation to cardiac vagal regulation in the first years of life

BACKGROUND

The Evolved Developmental Niche (EDN) is a millions-year-old developmental system that matches the maturational schedule of the offspring, optimizing health. Every animal has a developmental niche.

AIMS

Humanity has fallen away from providing its EDN. Does it matter?

STUDY DESIGN

Several components of humanity's EDN were reviewed (breastfeeding, positive touch, allomothers, responsive care, free play) in relation to cardiac vagal nerve regulation, a signal of healthy development. Focal subjects were young children.

OUTCOME MEASURES

A review of research on the selected EDN components in relation to vagal nerve function was performed. Data were available for all but the allomother component, which is typically not measured by western researchers, although allomothers provide EDN components alongside parents.

RESULTS

Apart from the lack of research on allomother effects, all these EDN components have been shown to influence cardiac vagal regulation in young children.

CONCLUSIONS

Converging evidence suggests that providing the EDN in early life may not only support aspects of a child's primal health system, but bolster capacities for social health and wellness, the cornerstone of a positive life trajectory.

Developmental diversity: Putting the development back into research about developmental conditions

The dominant discourse surrounding neurodevelopmental conditions such as autism and ADHD emphasizes biological explanations. Neurodevelopmental conditions are conceived as different types of brains, the result of different types of genes. This way of thinking is present both in medical research and in clinical practice. Indeed, it is widely acknowledged that the idea of having a biological diagnosis helps people see beyond blame and guilt. It aids acceptance. However, simplistic approaches to biology risks neglecting the experiences and stories of autistic people in favor of finding etiological causes. At the same time, there is growing awareness that risks, functioning, and resilience are not solely defined by genes and brains but have a cultural and experiential component as well. Furthermore, atypical cognitive trajectories are not straightforwardly associated with poor outcomes. In this paper we describe the concept of developmental diversity as an alternative to more categorical approaches to neurodevelopmental conditions. We explore how dynamic models of life offer possibilities to look at neurodevelopmental conditions differently: rather than seeing autistic people as people with fundamental flaws in their genes or software faults in their brains that have to be explained, autism appears as a phenomenon that exists in interaction with the context, as a meaningful reaction to the environment. We explore what it would mean for research to go from a diagnosis-based approach to a developmental diversity approach that will define wellbeing and functioning in a more granular way across developmental trajectories. We argue that this would mean incorporating lived experiences into biological research and going beyond genes-environment dichotomies. Next to yielding a more complete picture on the phenomenon of autism, we describe how an approach that takes developmental diversity as a starting point offers a new way to look at existing challenges of autism research, such as how to deal with the significant overlap between diagnosis. Our hypothesis is that thinking with developmental diversity rather than categorical difference both represents an opportunity for a more inclusive society, and fundamentally can alter the way we perform research. As such, it is in line with requests of neurodiversity and disability movements.

Developmental Consequences of Early Life Stress on Risk for Psychopathology: Longitudinal Associations with Children's Multisystem Physiological Regulation and Executive Functioning

The etiology of psychopathology is multifaceted and warrants consideration of factors at multiple levels and across developmental time. Although experiences of adversity in early life have been associated with increased risk of developing psychopathology, pathways toward maladaptation or resilience are complex and depend upon a variety of factors, including individuals' physiological regulation and cognitive functioning. Therefore, in a longitudinal cohort of 113 mother-child dyads, we explored associations from early adverse experiences to physiological co-regulation across multiple systems and subsequent variations in executive functioning. Latent profile analysis derived multisystem profiles based on children's heart rate, respiratory sinus arrhythmia, pre-ejection period, and cortisol measured during periods of rest and reactivity throughout a developmentally challenging protocol. Three distinct profiles of multisystem regulation emerged: heightened multisystem baseline activity (Anticipatory Arousal/ANS Responder), typically adaptive patterns across all systems (Active Copers/Mobilizers) and heightened HPA axis activity (HPA Axis Responders). Path models revealed that children exposed to adversity before 18-months were more likely to evidence an Anticipatory Arousal/ANS Responders response at 36-months, and children in this profile had lower executive functioning scores than the Active Copers/Mobilizers. In sum, these findings provide important information about potential physiological associations linking early adversity to variations in children's task-based executive functioning.

Prenatal psychosocial stress and children's sleep problems: Evidence from the ELSPAC-CZ study

Prenatal exposure to maternal stress may increase the risk of developing sleep problems in childhood. This study examined the association between prenatal stressful life events (PSLE) and children's sleep problems, taking into consideration their trajectory over time. Data were obtained from the Czech portion of the European Longitudinal Cohort Study of Pregnancy and Childhood (ELSPAC-CZ; N = 4,371 children). Mothers reported PSLE using an inventory of 42 life events and child sleep problems at five time-points (child age of 1.5, 3, 5, 7, and 11 years). The association was tested by a Poisson latent growth model, controlling for maternal and family demographics, birth characteristics, maternal depression, and alcohol use in pregnancy. The average rate of sleep problems was 2.06 (p < 0.001) at the age of 1.5 years and the rate of sleep problems decreased in a linear fashion over time (estimate = -0.118; p < 0.001). A higher number of PSLE was associated with a higher rate of sleep problems at the age of 1.5 years (incidence rate ratio [IRR] per interquartile range = 1.08, 95% confidence interval [CI] 1.05-1.12, p < 0.001) and with a reduced rate of decrease in sleep problems between the ages of 1.5 and 11 years (p < 0.001). Thus, PSLE were associated with chronicity of sleep problems in addition to their amount during early childhood. Prenatal exposure to stress may predispose individuals to the development of sleep problems in later life.

Maternal pineal melatonin in gestation and lactation physiology, and in fetal development and programming

Pregnancy and lactation are reproductive processes that rely on physiological adaptations that should be timely and adequately triggered to guarantee both maternal and fetal health. Pineal melatonin is a hormone that presents daily and seasonal variations that synchronizes the organism's physiology to the different demands across time through its specific mechanisms and ways of action. The reproductive system is a notable target for melatonin as it actively participates on reproductive physiology and regulates the hypothalamus-pituitary-gonads axis, influencing gonadotropins and sexual hormones synthesis and release. For its antioxidant properties, melatonin is also vital for the oocytes and spermatozoa quality and viability, and for blastocyst development. Maternal pineal melatonin blood levels increase during pregnancy and triggers the maternal physiological alterations in energy metabolism both during pregnancy and lactation to cope with the energy demands of both periods and to promote adequate mammary gland development. Moreover, maternal melatonin freely crosses the placenta and is the only source of this hormone to the fetus. It importantly times the conceptus physiology and influences its development and programing of several functions that depend on neural and brain development, ultimately priming adult behavior and energy and glucose metabolism. The present review aims to explain the above listed melatonin functions, including the potential alterations observed in the progeny gestated under maternal chronodisruption and/or hypomelatoninemia.

Maternal Stress During Pregnancy Predicts Infant Infectious and Noninfectious Illness

OBJECTIVES

To examine the association between prenatal stress and infant physical health in the first year of life within an understudied, racially and ethnically diverse, highly stressed community sample. We expected that greater stress exposure would predict higher rates of infant illness.

STUDY DESIGN

Low-income, racially/ethnically diverse, overweight women with low medical risk pregnancies were recruited (2011-2014) during pregnancy. Pregnancy Stressful Life Events were assessed retrospectively (mean, 11.88 months postpartum). Perceived stress was assessed twice during pregnancy (at a mean of 17.4 weeks and again at a mean of 25.6 weeks) and at 6 months postpartum. Women with live births (n = 202) were invited; 162 consented to the offspring study. Medical records from pediatric clinics and emergency departments for 148 infants were abstracted for counts of total infectious illnesses, total noninfectious illness, and diversity of illnesses over the first year of life.

RESULTS

The final analytic sample included 109 women (mean age, 28.08 years) and their infants. In covariate-adjusted negative binomial models, maternal perceptions of stress across pregnancy were positively associated with infant illness. Each 1-point increase in average stress was associated with a 38% increase in incidence of infant infections (Incidence rate ratio, 1.38; 95% CI, 1.01-1.88; P < .05), a 73% increase in noninfectious illness (IRR, 1.73; 95% CI, 1.34-2.23; P < .05), and a 53% increase in illness diversity (IRR, 1.53; 95% CI, 1.25, 1.88; P < .01); effect sizes were larger for perceived stress later in pregnancy. Stressful life events count and postnatal stress were not uniquely associated with illness.

CONCLUSIONS

In line with recommendations from the American Academy of Pediatrics to screen for maternal perinatal depression, screening and support for stress reduction during pregnancy may benefit both maternal and child health.

Sex differences in foetal origins of child emotional symptoms: a test of evolutionary hypotheses in a large, general population cohort

BACKGROUND

Based on previous findings from the Wirral Child Health and Development Study (WCHADS), and on evolutionary hypotheses, we preregistered analyses of data from a large epidemiological sample (https://osf.io/fn5g9/register/564d31db8c5e4a7c9694b2be), to test for sex-dependent moderation by prenatal maternal depressive symptoms of the association between postnatal maternal depressive symptoms and child emotional problems.

METHODS

A total of 8,354 mothers and children were followed from pregnancy to 3.5 years in the Avon Longitudinal Study of Parents and Children (ALSPAC). Self-report measures of prenatal and postnatal maternal depressive symptoms, and maternal report of child emotional symptoms were administered.

RESULTS

There was a three-way interaction between maternal prenatal and postnatal depression, and child sex (Coeff .042 95% CI 0.015 to 0.068, p = .002). This arose from moderation by prenatal depression, in opposite directions in boys and in girls. In boys, the association between postnatal depression and child emotional symptoms was weaker following lower prenatal depressive symptoms (interaction term coeff = .030, p = .001), and in girls, to a lesser extent, the association was stronger following lower prenatal depressive symptoms (interaction term coeff = -.012, p = .221).

CONCLUSIONS

We replicated the finding from the WCHADS that prenatal depression modifies the association between postnatal depression and children's emotional problems in a sex-dependent fashion. In ALSPAC, the sex difference was explained mainly by a protective effect of low prenatal depression in boys, while in WCHADS, it arose from greater vulnerability of girls to postnatal depression following low prenatal depression. In the light of these findings, in evaluating and implementing early interventions, there is need to consider that risks associated with postnatal depression may vary depending on maternal mood during pregnancy and may differ between boys and girls.

Implications of early life stress on fetal metabolic programming of schizophrenia: A focus on epiphenomena underlying morbidity and early mortality

The fetal origin of adult disease hypothesis postulates that a stressful in utero environment can have deleterious consequences on fetal programming, potentially leading to chronic disease in later life. Factors known to impact fetal programming include the timing, intensity, duration and nature of the external stressor during pregnancy. As such, dynamic modulation of fetal programming is heavily involved in shaping health throughout the life course, possibly by influencing metabolic parameters including insulin action, hypothalamic-pituitary-adrenal activity and immune function. The ability of prenatal insults to program adult disease is likely to occur as a result of reduced functional capacity in key organs-a "thrifty" phenotype-where more resources are re-allocated to preserve critical organs such as the brain. Notably, it has been postulated that the manifestation of neuropsychiatric disorders in individuals priorly exposed to prenatal stress may arise from the interaction between hereditary factors and the intrauterine environment, which together precipitate disease onset by disrupting the trajectory of normal brain development. In this review we discuss the evidence linking prenatal programming to neuropsychiatric disorders, mainly schizophrenia, via a "Thrifty psychiatric phenotype" concept. We start by outlining the conception of the thrifty psychiatric phenotype. Next, we discuss the convergence of potential mechanistic pathways through which prenatal insults may trigger epigenetic changes that contribute to the increased morbidity and early mortality observed in neuropsychiatric disorders. Finally, we touch on the public health importance of fetal programming for these disorders. We conclude by providing a brief outlook on the future of this evolving field of research.